Conventionally, such cable glands for armoured cables have been made from metal. The metal used is a good conductor. An example of a typical metallic gland design can be seen in cross-section in FIG. 1. The cable armour 120, which is typically a braid of metal wires, is revealed by stripping away the outer insulation of the cable and is forced against a metallic cone element 111. This in turn abuts the entry component 102 mounted on the enclosure, which is itself also metallic and conducting. This again abuts a metallic earth tag 101 which provides the connection to an external earth. An additional metal plate (not shown) may be needed at the interior edge of the enclosure wall if the wall is of plastics material. This is to ensure sufficient contact over variety of temperature ranges.
British patent 1228743 discloses an electrical connector including a cylindrical body of electrically insulating material. Any build-up of electrical charge on an outer component is prevented by means of a path to earth through a copper spring, a steel nut and washer, and the metal enclosure wall.
British patent 1505639 describes a cable gland for a sheathed cable which comprises a metal body and an insulator assembly. The insulator assembly includes a metal inner member and an insulating outer member. An earthed tag can be connected to the inner member, and an earthed stud can be tapped to the metal body.